/**
 * Created by Administrator on 2017/5/9.
 */

function A(){
    this.name = null;
}

A.prototype.setName = function(name){
    this.name = name;
}

var aa = new A();

console.log(typeof (aa.setName));
console.log(typeof (aa));
console.log((aa === null));

delete aa.setName;

console.log(typeof (aa));
console.log((aa === null));
console.log('::'+typeof (aa.setName));
console.log((aa.setName === null));

aa = undefined;

console.log(typeof (aa));
console.log((aa == null));